Techniques for detecting statuses of computers based on messages output from the computers have been known (see, for example, Japanese Laid-open Patent Publication No. 2008-225912). For example, when a failure occurs in a computer, a particular combination of messages may be output. A managing apparatus monitors whether or not messages output from a computer to be monitored include a pattern of messages indicating an occurrence of a failure to detect the occurrence of the failure. This pattern is a combination of messages that occur when the failure occurs and is stored in the managing apparatus in advance.
The messages output by the computer may be changed by a change in configuration, for example, by a software version upgrade. If the messages output from the computer are changed as mentioned, the managing apparatus is unable to recognize the change in the messages. Therefore, the managing apparatus is unable to detect the occurrence of the failure from the changed messages.